You will be surprised, but Buddhism is that very same "philosophy that distinguishes between harmful and beneficial". The notions of kusala (good, skilfull, healthy, conducive to comfort) and akusala (bad, incompetent, unwholesome, conducive to trouble) are central to Buddhism:
"Abandon what is unskillful (akusala), monks. It is possible to abandon what is
unskillful. If it were not possible to abandon what is unskillful, I
would not say to you, 'Abandon what is unskillful.' But because it is
possible to abandon what is unskillful, I say to you, 'Abandon what is
unskillful.' If this abandoning of what is unskillful were conducive
to harm and pain, I would not say to you, 'Abandon what is
unskillful.' But because this abandoning of what is unskillful is
conducive to benefit and pleasure, I say to you, 'Abandon what is
"Develop what is skillful (kusala), monks. It is possible to develop what is
skillful. If it were not possible to develop what is skillful, I would
not say to you, 'Develop what is skillful.' But because it is possible
to develop what is skillful, I say to you, 'Develop what is skillful.'
If this development of what is skillful were conducive to harm and
pain, I would not say to you, 'Develop what is skillful.' But because
this development of what is skillful is conducive to benefit and
pleasure, I say to you, 'Develop what is skillful.'" -- Kusala Sutta AN 2.19
In fact, Buddhism is so radically practical (much more radically than other philosophies) that it does not shy away from using tricks, like the fear of hell etc. because they too are kusala, conducive to benefit. Such tricks are called upaya ("skilfull means"). This is similar to how parents use tricks to protect their very young children who don't yet understand reason.
But just like upbringing the children is not limited to tricks, there is a lot more to Buddhism than upaya. What do we teach children? Proper behavior, Deep knowledge, and Hard work. Why do we teach them this? Because it will help them in their life.
Similarly, in Buddhism, we don't just scare people with hell. We teach them how to control their mind. Why? Because it helps them with their life! When mind is untrained, it gets easily obsessed by ideas. When mind is obsessed by ideas, it gets inflamed with emotions. Getting inflamed with emotions, one does not know what's good / what's bad. Then one starts acting based on this confused understanding of good and bad. And then one hurts oneself and others!
And vice versa, when mind is trained, it is not easily obsessed ==> not blinded with emotions ==> it clearly sees what's good / what's bad ==> and therefore it can act well. Very practical.
That's why they say Buddhism is good in the beginning, good in the middle and good in the end. When naive people follow it as religion, without understanding why, it protects them from harm -- this is good in the beginning. When people practice it seriously, taming their mind, it helps them handle all kind of life problems and increases social harmony -- this is good in the middle. Finally, when they solve the problem of Life-and-Death and achieve Completion -- this is good in the end.
And how do you tame the mind? First, by watching it continuously, every second of every minute of every hour, and identifying any sign of pathological clinging. Clinging to material possession, clinging to relationships and respect, clinging to comfort, well-being, stability, clinging to principles and ideals, clinging to fairness, clinging to skills, talents, intellect, success, control, clinging to plans for the future, clinging to spirituality, clinging to Buddhism, and even clinging to not-clinging! When you make anything all-important, you lose it and get very upset -- that's pathological clinging. As soon as you notice clinging, you must let go ASAP, otherwise it will get you in trouble. The feeling when you let go of clinging is like you are sobering up from liquor.
Second, mind is tamed by watching it for any signs of ego-motivated behavior. Whenever you notice yourself doing something seemingly right, but secretly (even from yourself) showing off, or defending your fault, or retaliating -- this is ego-motivated behavior. As soon as you notice even a little flavor of that, you need to surrender your ego to the world, which is acting as your teacher at that moment. This feels scary, similar to skydiving.
As you train like this very carefully, stalking yourself and keeping your mind free from even the smallest clinging or ego-motivated thought, within 5-10 years you will notice a huge positive difference in your life. This is basic training, this is how my teachers taught me -- as you see, it is very practical.
Now, to address the last part of your question, about "fear of getting into sadness" -- yes, Buddhism very much depends on the fact that people don't want to be sad, that people are afraid of suffering. This is how Buddhism defines good and bad, or kusala and akusala: good is what leads to happiness, and bad is what leads to suffering. This basic difference serves as the gasoline for the engine of Buddha-Yana (vehicle of awakening). One thing that Buddha was strongly against is nihilistic philosophy that denies distinction between good and bad.
So yes, Buddhism can be very useful to a modern practical society, but we need to go deeper, beyond the tricks of upaya and into the real practice of liberating the mind from pathological clinging and egoistic neuroses, and train it to not get obsessed with ideas and blinded with emotions, so it can clearly see what's good / what's bad for oneself and for everybody.